THE SOIL 



If people, in those days with new and fertile soils, could 

 use manures profitably, how much more ought we to use 

 them in our time when soils have lost their virgin fertility, 

 when the plant food in the soil has been exhausted by years 

 and years of cropping ! 



To sell ye^ar after year all the produce grown on land is 

 a sure way to ruin it. If, for example, the richest land is 

 planted every year in corn, and no stable or farmyard 

 manure or other fertilizer returned to the soil, the land 

 so treated will of course 

 soon become too poor to 

 grow any crop. If, on 

 the other hand, clover 

 or alfalfa or corn or cot- 

 ton-seed meal is fed to 

 stock, and the manure 

 from the stock returned 

 to the soil, the land will 

 be kept rich. Hence 

 those farmers who sell, 

 not such raw products as 

 cotton, corn, wheat, oats, 

 clover, but who market articles made from these raw prod- 

 ucts, find it easier to keep their land fertile. For illustration : 

 if instead of selling hay, farmers feed it to sheep and sell 

 wool; if instead of selling cotton seed, they feed its meal 

 to cows, and sell milk and butter ; if instead of selling 

 stover, they feed it to beef cattle, they get a good price 

 for products and in addition have all the manure needed 

 to keep their land productive and increase its value each 

 succeeding year. 



FIG. 14. RELATION OF HUMUS TO 

 GROWTH OF CORN 



(i) clay subsoil ; (2) same, with fertilizer ; 

 (3) same, with humus 



